DAX-1 expression in human breast cancer: comparison with estrogen receptors ER-alpha, ER-beta and androgen receptor status

Abstract

Background: So far there have been no reports on the expression pattern of DAX-1 (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1) in human breast cells and its relationship to the estrogen receptors, ER-alpha and ER-beta, and the androgen receptor (AR).

Methods: In this study we evaluated, by immunohistochemistry and Western blot analysis, the presence and distribution of DAX-1 in benign breast disease (BBD), in situ carcinoma (CIS), and ductal and lobular breast carcinomas.

Results: In BBD and breast carcinomas, DAX-1 was present in both the nuclei and the cytoplasm of epithelial cells, although in infiltrative carcinomas the percentage of nuclear immunoreaction was higher than in CIS. An important relation was observed between DAX-1 and AR expression and between this orphan receptor and nodal status.

Conclusion: DAX-1 might modify the AR and ER-beta intracellular location, and because a direct positive relation between the expression of these three receptors was found it could be assumed that the presence of DAX-1 in neoplastic cells might indicate a possible failure of endocrine therapies.

Figure 1

Immunoblots of ER-α, (a) ER-β, (b) AR, (c) and DAX-1 (d) in human breast. Relative molecular masses are shown at the left. Each blot is representative of its respective group. For all panels: lane 1, benign breast disease; lane 2, in situ carcinoma; lane 3, infiltrative ductal carcinoma; lane 4, infiltrative lobular carcinoma.

Figure 2

Expression of estrogen receptors ER-α, ER-β, androgen receptor (AR) and DAX-1 in human breast. (a–d) Immunohistochemistry of ER-α. (a) Negative immunoreaction in ductal hyperplasia (magnification × 300). (b) Sample of ductal carcinoma in situ (CIS) showing a strong immunolabelling of ER-α in the nuclei of neoplastic cells (magnification × 500). (c) A strong nuclear reactivity to ER-α antibody was observed in samples of infiltrative ductal carcinoma (IDC; magnification × 250). (d) ER-α was observed in the cytoplasm of some cells in infiltrative lobular carcinoma (ILC; magnification × 300). (e–h) Immunohistochemistry of ER-β. (e) Fibroadenoma was always negative to ER-β (magnification × 300). (f) Ductal CIS showing an intense cytoplasmic immunoreaction to ER-β (magnification × 400). (g) Positive reaction to ER-β in the cytoplasm of IDC cells (magnification × 250). (h) ILC showing cytoplasmic reaction to ER-β (magnification × 450). (i–l) Immunohistochemistry of androgen receptor (AR). (i) Negative reaction to AR antibody in hyperplasia (magnification × 300). In CIS (j) (magnification × 400) and IDC (k) (magnification × 200), cytoplasmic immunolabelling of AR was observed. (l) ILC showing cytoplasmic immunostaining of AR (magnification × 200). (m-p) Immunohistochemistry of DAX-1. An intense cytoplasmic reaction with granular pattern was observed in cases from ductal hyperplasia (m) (magnification × 200), CIS (n) (magnification × 600), IDC (o) (magnification × 600), and ILC (p) (magnification × 350). BBD, benign breast diseases.

Figure 3

Two-dimensional component plot showing the results of the principal components analysis obtained from the 39 patients with infiltrative carcinoma. A close correlation between DAX-1 immunoexpression, nodal status, and AR expression is observed. Component 1 is on the x-axis; component 2 is on the y-axis.